Recent research on human visual perception has shown that visual mechanisms exist which have selectivity for various stimulus features, including selective sensitivity for the direction in which a stimulus moves. These direction-specific movement detectors behave much like directionally selective neurons discovered using electrophysiological techniques in the visual systems of non-human mammals; this suggests that the human mechanisms are built from similar direction-sensitive cells. Until now, however, very little work has been undertaken which attempts to determine processes by which these mechanisms derive their selectivity, or to relate the operation of direction-specific mechanisms to the suprathreshold perception of motion. These questions warrant careful consideration, both on theoretical grounds and because answers may suggest methods for augmenting vision in individuals with several types of visual deficit. The objectives of this project include the following: a) to investigate the contribution of cross-correlation processes to the detection of moving targets; b) to determine whether discrimination of direction of movement of suprathreshold levels depends solely upon such correlation processes, or whether the perception of spatial displacement over time can be used successfully for such discrimination; c) to extend experiments conducted with one-dimensional drifting stimuli to more realistic two-dimensional cases; d) to examine the feasibility of aiding partially obscured vision by adding stimulus movement, sometimes in combination with a holographic imaging technique. Methods will include traditional psychophysical procedures, and experimental paradigms will include detection, discrimination, selective adaptation, and threshold additivity.